The Xbox One sold less than half of what its main competition, the PS4, managed to sell over the same period. It wasn't necessarily a failure though. Microsoft managed to salvage the console's reputation a few years into its release, turning it into a well-rounded machine that people could use for gaming or otherwise. However, despite the Xbox One's enduring popularity following the arrival of the Xbox Series S/X, Microsoft actually decided to pull the plug on the console back in 2020.
The Xbox Series S has effectively rendered the Xbox One moot
At one point, the Xbox One's reputation soured so much that the original Xbox creator thought that Microsoft would kill the brand. This didn't happen thanks to a series of savvy moves by Microsoft and Xbox Game Studios. The combination of the Xbox One's extensive backward compatibility library and all the subsequent upgrades eventually made the console worth the investment. But, while the Xbox One and Xbox One X both remain capable consoles these days, especially thanks to the Xbox Game Pass, Microsoft might have already killed it in favor of the Xbox Series S/X.